Biggest seat of the pants power increase I ever had was by fitting true duals 2 1/2". There wasn't a Cat in the system prior to fitting them (just a pipe in it's place), so the effect will be even better if you're removing the cat. At high rpms it felt a bit "strangled" & Dynomax ceramic coated Headers (1 5/8" - 3") sorted that out (O2 sensor mounted in reducer).
I also fitted a Crane 2040 CompuCam which woke it up a bit in the mid-high range, but it seemed to lose power off idle. Fitting a Hypertech thermomaster chip brought a lot of the low end grunt back. Whatever cam you decide on, it must have a good vacuum at idle, if not then the computer will start richening the mixture (as it'll think the engine is under load) as soon as you touch the throttle. This may cause it to bog & will definitely fail emmissions.
A free power increase is to advance the initial timing from the stock 6BTDC. Apparently you can go as high as 13BTDC but I went to 11BTDC for a safety margin. This simple adjustment really improved throttle response, especially off idle. Another throttle response improvement was gained by fitting a high output HEI coil & opening up the plug gaps by 5 thou.
I also fitted a Performer manifold, but can't really say if there was a difference (no doubt a dyno would tell the truth, it feels better, but dunno if there was extra power from it?).
1.52 roller tipped rockers probably gave a bit extra, again, it's hard to tell.
For gearing I fitted a 200-4r trans for the OD gear (BEST mod I EVER did, that OD is brilliant on the highway - now I can cruise with the "big boys" without the motor revving its heart out). The lower 1st gear ratio has improved off the line acceleration.
I've also fitted a 180 stat which was about the time that the TCC lockup inexplicably stopped working - maybe the computer didn't think the engine/trans was warm enough to lockup? Something to be aware of when fitting a lower temp stat. A 160stat tends to be a bit low for the computer & a few L81 owners haven't got on with them, but others have.
As mentioned, the CR & heads are the real plug in the system & I'm waiting for a set of AFR180's at the moment. They should really wake it up, even with the stock computer still controlling it. At the moment I don't think the cam is peforming as well as it could, simply coz the CR is a meagre 8.2:1 & the heads don't flow well. With good flowing heads & a CR somewhere above 9:1 I'm expecting the cam to start showing it's potential.
The E4ME performs well & also gives good economy, but they must be set up correctly. With Headers & running at around sea level, Headers casue the secondaries to run weak. Changing the stock CH rods to DA made a massive difference after the Headers were on, you can really feel it pulling. No mods were needed to the primaries as the computer controls the mixture automatically.
With no cat, Headers, duals (Monza "mufflers" - far from quiet), the cam & EGR/EFE removed, I put it through an exhaust sniffer test at it's last annual test (it's not a legal requirement, I was just interested). The hydrocarbon readings were very high, but after letting the motor warm up (as they should have done) another reading was taken. It was good, but I can't remember the figure. The CO reading was 0.14 (ppm?). Both readings impressed the testers as they've seen modern, small cars fitted with a cat & all the other smog stuff give worse readings on their 1st annual test (at the age of 3 years). The computer has to be doing something right to get readings as good as those!
I've definitely got more than the stock 190hp as I was behind a well cared for stock '80 as it left the lights at WOT. I went to WOT to keep up with it & had to let off real quick to avoid ploughing into the back of it!
I don't honestly think you'll get the full effects of FI as long as the stock smog heads are on & it's running the low stock CR. Change the heads, open up the exhaust, fit a better cam & you'll probably get a worthwhile increase from FI.
Cheers
